THE SUPERIOR MAXILLARY NERVE. 



The middle superior dental nerve leaves the superior maxillary in the hinder part 

 of the infraorbital canal, and is directed downwards and forwards in a special canal 

 in the outer wall of the antrum to the bicuspid teeth. 



The anterior superior dental nerve is the largest of the three. Arising near the 

 infraorbital foramen, it descends in its canal in the front wall of the antrum, and 

 divides into dental branches for the incisor and canine teeth, and a nasal branch, 

 which supplies the pituitary membrane in the fore part of the inferior meatus and 

 the adjoining part of the floor of the nasal fossa. 



The three dental nerves communicate so as to form loops with one another while 

 they are contained in their bony canals, and from these loops other branches spring, 

 which join again and give rise to a plexus (superior dental plexus) from which the 

 minute terminal filaments proceed to the teeth and gum. 



Facial branches. The facial branches are divisible into palpebral, nasal, and 

 labial sets. 



The inferior palpebral branches, generally an inner and an outer, ascend from 

 the termination of the infraorbital nerve to supply the skin and conjunctiva of the 

 lower eyelid in its whole breadth. 



The lateral nasal branches, two or three in number, are directed inwards between 

 the fibres of the levator labii superioris alaeque nasi muscle to the skin of the side of 

 the nose. 



The superior labial branches, the largest of the terminal offsets of the superior 

 maxillary nerve, and three or four in number, pass downwards between the elevator 

 muscles of the upper lip and of the angle of the mouth. Ramifying as they descend, 

 and giving off branches to supply the integument of the fore part of the cheek, 

 they end in the skin and mucous membrane of the upper lip. 



Below the orbit, the terminal branches of the superior maxillary nerve are joined 

 by considerable branches of the facial nerve, the union between the two being named 

 the infraorbital plexus. 



Spheno-Falatiue Ganglion. 



The spheno-palatine ganglion, also named MeckeVs or the nasal ganglion, is 

 deeply placed in the spheno-maxillary fossa, close to the spheno-palatine foramen. 

 It receives the two spheno-palatine branches which descend together from the 

 superior maxillary nerve as it crosses the top of the fossa. It is of a reddish-grey 

 colour, triangular in form, and convex on the outer surface, and measures from 

 before back about 5 mm. The grey or ganglionic substance contains multipolar 

 nerve-cells, and does not involve all the fibres of the spheno-palatine branches of the 

 upper maxillary nerve, but is placed at the back part, at the point of junction of the 

 Vidian nerve, so that many of the fibres of the spheno-palatine nerves proceeding 

 to the nose and palate pass to their destination without being incorporated with the 

 ganglionic mass. 



Branches proceed from the ganglion upwards to the orbit, downwards to the 

 palate, inwards to the nose, and backwards through the Yidian and pterygo-palatine 

 canals. 



ASCENDING BRANCHES. These are two or three very small twigs, which reach 

 the orbit by the spheno-maxillary fissure, and are distributed to the periosteum and, 

 according to Luschka, to the mucous membrane of the posterior ethmoidal and 

 sphenoidal sinuses. 



Bock and Valentin describe a branch ascending- from the gang-lion to the sixth nerve ; 

 Tiedemaim, one to the lower angie of the ciliary gang-lion. Hirzel and Arnold traced fila- 

 ments to the optic nerve or its sheath. 



